The present invention relates to a photosensitive resin composition or, more particularly, to a heat-resistant photosensitive resin composition suitable for use in the manufacture of printed circuit boards having excellent heat resistance, adhesion and high photosensitivity to satisfy the requirements for a solder resist, etching resist and plating resist.
It is well known in the prior art to use a photosensitive resin as a solder resist, etching resist or plating resist in the manufacturing process of printed circuit boards. Various kinds of photosensitive resins or photosensitive resin compositions have been proposed hitherto and are practically used for the purpose.
For example, the solder resist disclosed in Japanese Patent Kokai No. 60-208377 comprises a phenol novolac-type or cresol novolac-type epoxy resin having an ethylenically unsaturated group, a photopolymerization initiator and an amine-based curing agent. The heat-resistant photosensitive resin composition disclosed in Japanese Patent Kokai No. 58-199341 comprises a diallyl phthalate prepolymer, a photopolymerizable monomer and a photopolymerization initiator. Further, the photopolymerizable resin composition disclosed in Japanese Patent Publication No. 52-43090 comprises a linear polymeric compound having an N-alkoxymethyl carbamoyl group as the pendant group and a compound having at least two epoxy groups in a molecule.
These heat-resistant photosensitive resin compositions are advantageous in respect of the excellent resistance against heat and chemicals but, in contrast therewith, have a defect that the developer for the development treatment thereof is limited to some special organic solvents such as chlorinated hydrocarbon solvents to cause an economical disadvantage due to the expensiveness of the organic solvents used as the developer.
Besides, it is a trend in recent years to minimize the amount of use of chlorinated hydrocarbon solvents from the standpoint of decreasing the problems of environmental pollution and workers' health so that the number of the organic solvents usable as a developer in the development treatment of these heat-resistant photosensitive resin compositions is decreased less and less.
With an object to solve the above described problems, development works have been undertaken to obtain a heat-resistant photosensitive resin composition capable of being developed with water or an aqueous alkaline solution as the developer although no practically satisfactory photosensitive resin composition has yet been obtained due to the poor resistance against heat and chemicals as well as in respect of the poor adhesion to the substrate surface and stability in storage.